import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:小葱的01串
 * User: wangxin
 * Date: 2024-08-11
 * Time: 17:16
 */
public class test3 {

    public class Main
    {
        public static void main(String[] args)
        {
            Scanner in = new Scanner(System.in);
            int n = in.nextInt();
            char[] s = in.next().toCharArray();

            int[] sum = new int[2]; // 统计字符串中所有 0 和 1 的个数
            for(int i = 0; i < n; i++)
            {
                sum[s[i] - '0']++;
            }

            int left = 0, right = 0, ret = 0, half = n / 2;
            int[] count = new int[2]; // 统计窗⼝内 0 和 1 的个数
            while(right < n - 1) // 细节问题
            {
                count[s[right] - '0']++;
                while(right - left + 1 > half)
                {
                    count[s[left++] - '0']--;
                }
                if(right - left + 1 == half)
                {
                    if(count[0] * 2 == sum[0] && count[1] * 2 == sum[1])
                    {
                        ret += 2;
                    }
                }
                right++;
            }

            System.out.println(ret);
        }
    }
}
